For the given position vectors r(t) compute the unit tangent vector T(t) for the given value of t. If r(t)=(cos2t, sin2t) Then T(4pi)= ( , ) If r(t)=(t2, t3) Then T(5)=( , ) If r(t)=e2ti+e-5tj+tk. Then T(1)= i+ j+ k.